Apparatus for straightening metal strips

ABSTRACT

In a machine of the type having upper and lower straightening rolls and support rollers for straightening a metal strip of indeterminate length; the support rollers on which the lower straightening rolls rest, are arranged in a staggered manner so that a group of support rolls which is in engagement with one particular straightening roll does not contact any other straightening roll.

Int. Cl. ..'B2 ld 1/02 I O United States Patent [191 [111 3,818,739

Miinchbach et al. [4 June 25 1974 APPARATUS FOR STRAIGHTENING [58] Field of Search 72/ 163, I65. 205

METAL STRIPS [75] Inventors: Curt Miinchbach, [56] References Cited Pforzheim-Sonnenberg; Hans UNITED STATES PATENTS Weber, Neuenburg, both of 3,326,026 6/1967 Guillot 72/163 Germany [73] Assignee: Irma Ungerer, Pforzheim, Germany Primary Examiner-Milton 3 M [22] iled July 26 19 1 Attorney, Agent, or Firm-Edwin E. Greigg [2]] App]. No.: 164,841 [57] ABSTRACT Related s Application Data In a machine of the type having upper and lower [63] continuation of No 765 313 Oct 7 1968 straightening rolls and support rollers for straightening abandoned a metal strip of indeterminate length; the support rollers on yvhich the lower straightening rolls rest, are ar- [30] Foreign Application Priority Data ranged in a staggered manner so that a group 0t" sup- 0 27 I 967 G 14342 port rolls whlch 1s m engagement with one particular emanym" straightening roll does not contact any other straight- 52 us. Cl. 72/163 enmg 2 Claims, 7 Drawing Figures APPARATUS FOR STRAIGHTENING METAL STRIPS CROSS REFERENCE TO RELATED APPLICATION BACKGROUND OF THE INVENTION The invention relates to machines for straightening a metal strip passed therethrough in a tensioned condition. The straightening operation itself is performed by straightening rolls held by support rolls or support rollers.

The straightening operation in straightening machines is effected by alternately bending, to one side and the other, the metal strip passing through the apparatus. At and nearthe surface of the strip thebending stresses exceed the flow limit. Particularly in the case of thin metal strips, however, the flow limit often does not extendas deep as the neutral axis following the alternate bending and consequently,'the strip does not deform plastically and uniformly across its entire crosssection. Although a strip so straightened may optically appear to be planar, it is not free from internal stresses. These residual stresses may be of different magnitudes at different locations; this way have'an undesirable effect during subsequent use of the product.

For the aforenoted reasons, insteadof using a straigtening machine, thin and very thin metal sheets or strips having a thickness of 0.06 to 0.8 millimeter are straightened by means of simple stretching which is performed along a strip length tensioned between a roll assembly also designated as an S-assembly. Such S- assemblies include a plurality of parallel rolls of relatively large diameters (for example, 600 to 1,000 millimeters) around which the strip is trained to pass in a simple or multiple S-form. It is advantageous that the strip surrounds the rolls over a large angle so that substantialfrictional forces may be transmitted. One of two such S-assemblies serves to hold back the running strip against the pulling force imparted thereto so that a hold-back pull" is generated. The second S- assembly pulls the strip against the hold-back force and is adjustable to vary the pulling force for controlling the tension of the strip. It is known to provide a straightening machine between such S-assemblies to obtain, even in the case of thicker strips, better straightening results than if a straightening machine alone is used. Thus, with such an arrangement the versatility of these machines may be increased without the necessity of augmenting the stretching force. This result may be achieved with a pulling force which is substantially smaller than a sole pulling force thatwould cause flowing of the strip.

In known straightening machines the straightening rolls usually rest on supporting rolls or rollers, each of which supports two adjacent straightening rolls. Thus, a support roll-or roller is disposed in such a manner between two adjacent straightening rolls that it is in contact with both.

During the straightening operation perfonned by the above outlined machines on metallic strips drawn therethrough under a stretching tension, undesirable slip marks appear on the surface thereof.

OBJECT AND SUMMARY OF THE INVENTION A It is an object of the invention to provide an improved apparatus for straightening metal strips without leaving slip marks thereon.

The invention is based on the recognition that the supporting rollers or rolls which simultaneously contact adjacent straightening rolls, effect a coupling therebetween by virtue of a transferable friction force appearing during the application of the straightening pressure. Due to the aforenoted coupling, adjacent straightening rolls are constrained to rotate with exactly the same speed. When, however, a strip is passed through the straightening machine under a stretching pull, it increases in length as it passes from one straightening roll to an adjacent one, so that strip lengths of different magnitudes pass over adjacent straightening rolls during identical lengths of time. Thus, if it is desired to avoid slip marks on the sensitive surfaces of the strips, the straightening rolls should rotate at different speeds.

- Briefly stated, according to the invention, each straightening roll is supported only by support rollers associated with that straightening roll alone, that is, each support roll or roller is in contact only with one straightening roll. Accordingly, in a preferred embodiment of the invention, each of the straightening rolls rests, as in known apparatus, on a plurality of support rollers arranged in rows along the length of each straightening roll at identical heights. The rollers of each row are disposed in an alternately staggered manner so that in each instance one particular support roller is in contact with a first straightening roll while the next support roller of the same row engages an adjacent straightening roll.

As a result of the aforenoted arrangement, the rotational speed of each straightening roll may adjust itself to the speed of the passing strip independently of the rotational speed of adjacent straightening rolls. This arrangement ensures that there will be no slippage of the strip on any of the straightening rolls and consequently, no slip marks will appear on the surface of the strip.

The invention will be better understood and further objects and advantages will become more apparent from the ensuring detailed specification of two exemplary embodiments taken in conjunction with the draw- BRIEF DESCRIPTION OF THE DRAWINGS FIG. 6 is a partial schematic plan view of a second embodiment; and

FIG. 7 is a sectional view along line VII-VII of FIG. 6.

BRIEF DESCRIPTION OF THE PRIOR ART Turning now to FIGS. 1 and 2, there is schematically shown a conventional straightening arrangement including radially spaced, horizontally juxtaposed upper straightening rolls 1 (only one shown) and radially spaced, horizontally juxtaposed lower straightening rolls 2, each of the latter resting on a plurality of axially spaced rollers 3. It is seen from FIG. 2 that each support roller 3 (with the exception of the first and last roller) is in contact with two adjacent straightening rolls 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to FIGS. 3 to 5, it is seen that the lower straightening rolls 23, 24 and 25 rest on a plurality of support rollers which are disposed at identical heights in successive rows parallel with the straightening rolls and which may be vertically adjustable in a known manner. The support rollers form a first group consisting of rollers 4 and a second group consisting of rollers 5. Each row of support rollers consists of a plurality of rollers 4 and 5 arranged alternately and disposed in such a manner that support rollers 4 forming said first group are staggered or offset laterally to their axis by a distance a (FIG. 3) with respect to support rollers 5 forming said second group. Such an arrangement is best shown in FIG. 4. It is seen from FIG. 3 that each individual lower straightening roll is supported only by one group of support rollers which are not in engagement with any other straightening roll. Thus, as best seen in FIG. 3, the straightening roll 23 rests on support rollers 4 of a first and adjacent second row, the straightening roll 24 is engaged by support rollers 5 of said second row and an adjacent third row, while straightening roll 25 is supported by support rollers 4 of said third row, etc. Stated in dilferent terms, each straightening roll has a cradle-like support formed of at least one pair of support rollers. Any one straightening roll may rest on several pairs of support rollers, all belonging, however, to the same group. By virtue of the aforedescribed arrangement, any one support roller is in contact only with a sole straightening roll. It is to be understood that each straightening roll may be associated with a great plurality of support rollers arranged along its length.

Thus, in FIG. 4, axially adjacent the support rollers 5 there may be arranged another series or column of support rollers 4, then again a column of rollers 5, etc. As seen in FIGS. 4 and 5, adjacent support rollers 4 and 5 are held by their stub shafts in the side walls of forked carriers 6.

' DESCRIPTION OF A SECOND EMBODIMENT The embodiment shown in FIGS. 6 and 7 differs from the afore-described embodiment in that the forked carriers 7 hold narrow outer support rollers 8 which are arranged coaxially, while therebetween there are arranged wider support rollers 9, the axis of which is set off with respect to the axis of support rollers 8. In such an arrangement a first straightening roll (not shown) rests on a pair of support rollers 8 and an immediately adjacent second straightening roll (not shown) rests on a support roller pair 9.

What is claimed is:

1. In an apparatus for straightening, under a stretching pull, a metal strip of indetermined length passed therethrough, said apparatus being of the type including at least two adjacent juxtaposed parallel straightening rolls resting on a plurality of support rollers, the improvement residing in the arrangement of said support rollers whereby each of said straightening rolls rests on at least one pair of support rollers forming a cradle-like support for each straightening roll, with each support roller being in engagement with a sole straightening roll and having a rotational axis stationary with respect to the associated straightening roll to prevent deflection of the latter by said pull exerted on said strip in the direction of its travel, and with each pair of support rollers forming a separate group of rollers which are offset from each other in the direction of the rotational axes of the rollers such that the distance between the adjacent straightening rollers is less than the diameter of either of the straightening rollers.

2. In an apparatus for straightening, under a stretching pull, a metal strip of indetermined length passed therethrough, said apparatus being of the type including a plurality of juxtaposed parallel straightening rolls resting on a plurality of support rollers, the improvement residing in the arrangement of said support rollers whereby each of said straightening rolls rests on at least one pair of support rollers forming a cradle-like support for each straightening roll, with each support roller being in engagement with a sole straightening roll and having a rotational axis stationary with respect to the associated straightening roll to prevent deflection of the latter by said pull exerted on said strip in the di rection of its travel; and wherein said support rollers form a first and a second group, with said rollers being disposed in rows parallel with and below said straightening rolls, with each of said rows being constituted by alternating rollers of said first and said second group, with the rollers of said first group in each row being offset with respect to the rollers of said second group in the same row, and with every other straightening roll resting solely on rollers of said first group in two adjacent rows and every straightening roll positioned in between two of the aforenamed straightening rolls resting solely on rollers of said second group in two adjacent rows. 

1. In an apparatus for straightening, under a stretching pull, a metal strip of indetermined length passed therethrough, said apparatus being of the type including at least two adjacent juxtaposed parallel straightening rolls resting on a plurality of support rollers, the improvement residing in the arrangement of said support rollers whereby each of said straightening rolls rests on at least one pair of support rollers forming a cradlelike support for each straightening roll, with each support roller being in engagement with a sole straightening roll and having a rotational axis stationary with respect to the associated straightening roll to prevent deflection of the latter by said pull exerted on said strip in the direction of its travel, and with each pair of support rollers forming a separate group of rollers which are offset from each other in the direction of the rotational axes of the rollers such that the distance between the adjacent straightening rollers is less than the diameter of either of the straightening rollers.
 2. In an apparatus for straightening, under a stretching pull, a metal strip of indetermined length passed therethrough, said apparatus being of the type including a plurality of juxtaposed parallel straightening rolls resting on a plurality of support rollers, the improvement residing in the arrangement of said support rollers whereby each of said straightening rolls rests on at least one pair of support rollers forming a cradle-like support for each straightening roll, with each support roller being in engagement with a sole straightening roll and having a rotational axis stationary with respect to the associated straightening roll to prevent deflection of the latter by said pull exerted on said strip in the direction of its travel; and wherein said support rollers form a first and a second group, with said rollers being disposed in rows pArallel with and below said straightening rolls, with each of said rows being constituted by alternating rollers of said first and said second group, with the rollers of said first group in each row being offset with respect to the rollers of said second group in the same row, and with every other straightening roll resting solely on rollers of said first group in two adjacent rows and every straightening roll positioned in between two of the aforenamed straightening rolls resting solely on rollers of said second group in two adjacent rows. 